"Rod Speed" ha scritto nel messaggio
Giusi wrote

because a tank water heater works 24/7 no matter how cheap

Plenty of the water heaters dont store the hot water.

I have that type of water heater, but it takes a lot of water running before
the water is hot.

The dishwasher fills with a couple of liters of water, rinses, drains,
then 3 liters that it heats.

Yes, but a dishwasher that uses piped hot water doesnt have to use hot
water all the time.

Nor does mine use all hot. There is a prewash rinse that is cold, and maybe
the first rinse is cold. How would I know?

We are encouraged to use our dishwashers in Italy because it uses less
water and energy than handwashing.

The energy claim is very dubious, particularly with drying.

We do not have heated drying in our DWs. It dries using reserved heat from
a superhot rinse cycle. You can hear silence for a period followed by the
sound of the drain opening. The dishes are very hot. On occasion I have
opened it right away to get something I wanted and burned my fingers, but
there is not hot air period that follows that rinse.